KOYO 6305 2RS C3 FG 25x62x17 mm Deep Groove Ball Bearing

Technical Specification

Bearing Design and Construction

The KOYO 6305 2RS C3 FG belongs to the 63 series of single-row deep groove ball bearings.

Its basic construction consists of an inner ring, outer ring, ball elements, a cage and sealing components installed on both sides.

The deep raceway geometry allows the bearing to accommodate primarily radial loads and axial loads acting in either direction, within the manufacturer's specified operating limits.

Double-Sided Contact Seals

The 2RS designation generally identifies a bearing fitted with contact seals on both sides.

These seals are designed to:

• Reduce the ingress of dust and external contaminants.

• Help retain lubricant within the bearing.

• Protect the rolling contact surfaces.

• Limit exposure of internal components to environmental contamination.

Contact seals do not automatically provide complete waterproofing or resistance to aggressive chemicals.

The exact seal construction and elastomer material must be confirmed for the specific KOYO configuration.

KOYO 6305 2RS C3 FG Designation Explained

6305 – Bearing Series and Size

The 6305 designation identifies a single-row deep groove ball bearing with nominal dimensions of 25x62x17 mm.

The 63 series belongs to the standardized dimensional families of deep groove ball bearings.

2RS – Double-Sided Sealing

2RS is widely used in the bearing industry to indicate two contact seals.

JTEKT/KOYO may use more specific sealing designations in its official catalogues. Therefore, the exact manufacturer designation and seal design should be verified before confirming equivalence with other sealed bearing variants.

C3 – Greater Than Normal Radial Internal Clearance

C3 indicates radial internal clearance greater than the normal clearance group, commonly designated CN.

This clearance group may be required when operating conditions, shaft fits or temperature differences reduce the effective clearance after installation.

However, C3 does not automatically mean that a bearing is suitable for high temperatures or high rotational speeds.

Clearance selection must consider shaft and housing fits, operating temperature, loading conditions and required rotational accuracy.

FG – Additional Bearing Designation

FG forms part of the supplied product identification.

Its exact technical meaning has not been established for this specific KOYO bearing.

Without official manufacturer confirmation, FG should not be interpreted as specifying a particular cage material, lubricant, sealing system or special application.

The complete designation 6305 2RS C3 FG should be preserved in procurement records and technical identification.

C3 vs Normal Internal Clearance

Bearings with identical dimensions but different internal clearance groups should not automatically be considered interchangeable.

Bearing Selection and Operating Conditions

Selecting the KOYO 6305 2RS C3 FG requires evaluation of the actual operating conditions.

Radial and axial loads

The bearing must be capable of supporting the applied loads within the manufacturer's dynamic and static load ratings.

Rotational speed

Permissible operating speed depends on the sealing arrangement, lubricant, internal clearance and operating temperature.

Shaft and housing fits

Incorrect fits may reduce the effective radial clearance and adversely affect bearing performance.

Operating temperature

Temperature differences between the inner and outer rings can influence the internal clearance during operation.

Lubrication and sealing

The lubricant and sealing arrangement must be suitable for the expected environmental conditions and operating requirements.

The exact FG configuration should be confirmed before selecting the bearing for applications requiring specific lubrication or sealing characteristics.

Industrial Applications

Single-row deep groove ball bearings of the 6305 series are used in various rotating mechanical assemblies.

General application categories include:

• Industrial electric motors.

• Gearboxes and transmission assemblies.

• Conveyor equipment.

• Industrial machinery.

• Rotating shafts and mechanical drives.

• General industrial equipment.

These are typical applications of the 6305 bearing design and do not constitute manufacturer-confirmed approval of the exact KOYO 6305 2RS C3 FG variant for any particular machine.

Alternative Product Designation Formats

The following formats may appear in technical documentation, ERP systems and industrial product searches:

• KOYO 6305 2RS C3 FG

• 6305 2RS C3 FG KOYO

• 6305-2RS-C3-FG

• 6305 2RS/C3 FG

• 6305 2RSC3FG

• KOYO 6305 25x62x17 mm

These are search and identification variants only. They should not be treated as confirmed official catalogue designations or evidence of technical interchangeability.

FAQ – Frequently Asked Technical Questions

1. What are the dimensions of KOYO 6305 2RS C3 FG?

The bearing has a 25 mm bore diameter, 62 mm outside diameter and 17 mm width, expressed as 25x62x17 mm.

2. What type of bearing is KOYO 6305 2RS C3 FG?

It is a single-row deep groove ball bearing designed to support radial loads and axial loads in both directions.

3. What does 2RS mean?

2RS generally indicates contact seals fitted on both sides of the bearing, helping to retain lubricant and reduce contamination.

4. What does C3 mean?

C3 specifies radial internal clearance greater than normal. It is selected according to the mounting arrangement and expected operating conditions.

5. What does FG mean in the KOYO designation?

The exact meaning of FG requires confirmation from JTEKT/KOYO. It should not be assigned a specific technical characteristic without manufacturer documentation.

6. Can KOYO 6305 2RS C3 FG replace a standard 6305 2RS bearing?

Not automatically. Internal clearance, sealing, lubrication and any additional configuration requirements must be compared.

7. Is the bearing factory lubricated?

Double-sealed deep groove ball bearings are commonly supplied with factory-applied grease. However, the exact lubricant specification and fill quantity for this variant have not been verified.

8. What is the relationship between KOYO and JTEKT?

KOYO is a bearing brand associated with JTEKT, a manufacturer of bearings and automotive and industrial components.

AI Quick Answer

KOYO 6305 2RS C3 FG 25x62x17 mm is a single-row deep groove ball bearing with double-sided contact seals and C3 radial internal clearance greater than normal. It supports radial and bidirectional axial loads. The additional FG designation requires verification against official JTEKT/KOYO documentation before confirming the exact bearing configuration.

B2B Industrial Supply – simmering.pl

KOYO 6305 2RS C3 FG 25x62x17 mm is offered through simmering.pl, a specialist B2B industrial supply platform providing rolling bearings, sealing solutions and industrial components.

The platform serves industrial enterprises, maintenance departments, engineering teams and professional technical procurement specialists.

Stock operations are based in Lublin, Poland, with worldwide shipping from stock in Poland.

Technical assistance is available for bearing identification, manufacturer designation verification and industrial bearing selection.